问Java GridLayout和添加按钮的问题

EN

    public class GamePanel extends JPanel {
    GameUI controler;
    GridLayout gameLayout = new GridLayout(10,10);
    JButton gameButtons[] = new JButton[100];
    ImageIcon ice;
    JButton startButton;
    JButton exitButton;
    ImageIcon startIcon;
    ImageIcon exitIcon;
    URL urlIcon;
    private int i;

    public GamePanel(GameUI controler) {
        this.setLayout(gameLayout);
        this.controler = controler;
        urlIcon = this.getClass().getResource("/icons/Overlay.png");
        ice = new ImageIcon(urlIcon);
        makeButtons();
    }

    @Override
    public void paint(Graphics g) {
        super.paint(g);
    }

    public void makeButtons() {
        for(i = 0; i< 100; i++) {
            gameButtons[i] = new JButton(ice);
            this.add(gameButtons[i]);
            revalidate();   
        }
        repaint();
    }
}

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;

import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.net.URL;


public class GameUI extends JFrame {

ImageIcon i;
Image jFrameBackground;
JButton startButton;
JButton exitButton;
ImageIcon startIcon; 
ImageIcon exitIcon;


public GameUI() {
    setResizable(false);
    this.setSize(1200, 800);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    this.setLayout(null);








    BackGroundPanel backGroundPanel = new BackGroundPanel();
    GamePanel panel = new GamePanel(this);
    ButtonPanel buttonPanel = new ButtonPanel();

    panel.setSize(500,500);
    panel.setLocation(100, 150);
    backGroundPanel.setSize(this.getWidth(),this.getHeight());
    backGroundPanel.setLocation(0,0);
    buttonPanel.setSize(390,50);
    buttonPanel.setLocation(100,100);
    this.add(backGroundPanel);
    this.add(panel);
    this.add(buttonPanel);




    backGroundPanel.setBackground(Color.BLACK);



}





public static void main(String[] args) throws InvocationTargetException, InterruptedException {







    javax.swing.SwingUtilities.invokeAndWait(
                new Runnable(){

                    @Override
                    public void run() {



                        GameUI ui = new GameUI();
                        ui.setVisible(true);


                    }


                }

            );




}